Prototypes of single-beam and multibeam flow cytometers incorporating flow chambers with integrated optical systems and personal computer-based subsystems for data acquisition and analysis will be built and their performance evaluated in comparison with flow cytometers of conventional design. Performance evaluation will be based on determination of the sensitivity and precision of measurements of fluorescence, extinction, and light scattering of plastic spheres and of cultured cells and nuclei stained with DNA and RNA fluorochromes, fluorescently labeled antibodies, and other fluorescent reagents. High speed communication over telephone lines will be used to link flow cytometers with each other and with a computer at a remote site, to test the feasibility of remote operation, maintenance, and support. A fast digital processor will be compared to a hardwired hybrid electronic system as an instrument controller for flow cytometers. It is anticipated that the apparatus to be evaluated in this project will be significantly less expensive and easier to operate than existing flow cytometers, thus making this increasingly useful technology more widely accessible.